Wetland Assessment for Areas Associated with the Weltevreden … · 2018-01-20 · Wetland Assessment Wetland Assessment for Areas Associated with the Weltevreden Site NOR1982 Digby

_______________________________________________________________________________________ Digby Wells and Associates (South Africa) (Pty) Ltd (Subsidiary of Digby Wells & Associates (Pty) Ltd). Co. Reg. No. 2010/008577/07. Fern Isle, Section 10, 359 Pretoria Ave Randburg Private Bag X10046, Randburg, 2125, South Africa Tel: +27 11 789 9495, Fax: +27 11 789 9498, [email protected], www.digbywells.com _______________________________________________________________________________________ Directors: A Sing*, AR Wilke, DJ Otto, GB Beringer, LF Koeslag, AJ Reynolds (Chairman) (British)*, J Leaver*, GE Trusler (C.E.O) *Non-Executive _______________________________________________________________________________________

Wetland Assessment for Areas

Associated with the Weltevreden

Site

Wetland Assessment

Project Number:

NOR1982

Prepared for:

Northern Coal (Pty) Ltd

July 2014

http://www.digbywells.com/

Digby Wells Environmental i

This document has been prepared by Digby Wells Environmental.

Report Type: Wetland Assessment

Project Name: Wetland Assessment for Areas Associated with the

Weltevreden Site

Project Code: NOR1982

Name Responsibility Signature Date

Crystal Rowe Report Compiler

2014-07-28

Andrew Husted Review

2014-07-28

This report is provided solely for the purposes set out in it and may not, in whole or in part, be used for any other purpose

without Digby Wells Environmental prior written consent.

Wetland Assessment

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Digby Wells Environmental ii

EXECUTIVE SUMMARY

Digby Wells & Associates (DWA) was appointed by Northern Coal (Pty) Ltd to undertake a

wetland study on the farm Weltevreden in the Belfast area, Mpumalanga. An opencast mine,

comprised of three pits and associated infrastructure, is intended for the area. A Wetland

Assessment Report has already been completed in 2008, by Digby Wells and the purpose of

the current assessment is to update this report. The aim of the study is to delineate wetland

areas, classify wetlands, describe the Present Ecological State (PES), functionality and

sensitivity of wetlands and to provide an impacts assessment to determine the potential

impacts of the development and operation of the proposed opencast mine on wetlands on

site.

The study area falls within the Komati River catchment (X11D), which is in a moderately

modified state. Three wetlands have been identified by NFEPA, two of which are regarded

as important for the maintenance of biodiversity. In addition, Mpumalanga C-Plan classifies

wetlands on site as ‘natural’ but does not regard any of them as critical for meeting the

objectives of this plan.

The wetlands on site were delineated making use of the four primary indicators, namely: soil

form, soil wetness features, vegetation and terrain. Based on this, 160.3 ha of wetland areas

was delineated, the majority of which was classified as hillslope seepage. The remaining

wetlands were hillslope seeps leading to channels, hillslope seeps leading to pans and a

single pan / depression.

Wetlands were largely allocated a PES of C, as well as D; with the major impacts related to

damming, overgrazing and trampling by livestock, as well as the presence of roads that

cause compaction of sediments and reduced flow of water through the wetland. 60% of

wetlands were assigned an Ecological Importance and Sensitivity (EIS) of C and the

remainder were assigned an EIS of D (40% of wetlands on site).

The primary impacts associated with the proposed opencast mine is direct loss of wetland

habitat. This will cause a reduction in available habitat for flora and fauna and will also result

in a loss of eco-services provided. Further to this, the risk of hydrocarbon spills and

contamination of surface water from mining activity is regarded as highly significant as the

major degradation to wetlands can occur. The 100m buffer, as stipulated by the National

Water Act (No. 36 of 1998) has been recommended for all wetlands on site. Fortunately the

Weltevreden pan and its narrow catchment have been excluded from the current mine plan.

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Digby Wells Environmental iii

TABLE OF CONTENTS

1 Introduction ....................................................................................................................... 1

1.1 Terms of Reference ................................................................................................. 3

2 Study Area ........................................................................................................................ 4

2.1 Drainage and Quaternary Catchments .................................................................... 6

2.2 National Freshwater Ecosystem Priority Areas (NFEPA) ......................................... 8

2.3 Mpumalanga Conservation Plan (C-Plan) ............................................................. 11

3 Expertise of the Specialist ............................................................................................... 13

4 Aims and Objectives ....................................................................................................... 13

5 Methodology.................................................................................................................... 13

5.1 Wetland Identification and delineation ................................................................... 13

5.2 Wetland Delineation .............................................................................................. 15

5.3 Wetland Ecological Health Assessment ................................................................ 15

5.4 Wetland Ecological Importance and Functionality Assessment ............................. 16

5.5 Wetland Functional Assessment ........................................................................... 16

5.6 Impact Assessment ............................................................................................... 17

6 Results ............................................................................................................................ 19

6.1 Wetland delineation ............................................................................................... 19

6.1.1 Vegetation Indicator ........................................................................................ 22

6.1.2 Soil Indicator ................................................................................................... 24

6.1.3 Terrain Indicator ............................................................................................. 24

6.2 Wetland Functionality ............................................................................................ 27

6.3 Wetland Present Ecological State (PES) ............................................................... 30

6.4 Wetland Ecological Importance and Sensitivity (EIS) ............................................ 32

7 Impacts Assessment ....................................................................................................... 34

7.1 Issue 1: Loss of wetland area ................................................................................ 36

7.1.1 Impact 1 - Loss of hillslope seeps ................................................................... 36

7.1.2 Impact 2 - Loss of Valley Bottom Wetlands ..................................................... 37

7.2 Issue 2: Loss of wetland integrity and functionality ................................................ 37

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Digby Wells Environmental iv

7.2.1 Impact 3: Chemical contamination of surface water ........................................ 37

7.3 Cumulative Impacts ............................................................................................... 39

7.4 Impact mitigation hierarchy .................................................................................... 40

8 Discussion ....................................................................................................................... 41

9 Recommendations .......................................................................................................... 41

10 Conclusions ..................................................................................................................... 43

11 References ...................................................................................................................... 44

LIST OF FIGURES

Figure 2-1: Locality ............................................................................................................... 5

Figure 2-2: Quaternary Catchments ...................................................................................... 7

Figure 2-3: NFEPA wetlands associated with the study area .............................................. 10

Figure 2-4: Mpumalanga C-Plan ......................................................................................... 12

Figure 5-1: Wetland HGM Units (modified from Brinson 1993; Kotze 1999 and Marneweck

and Batchelor 2002) ............................................................................................................ 14

Figure 6-1: Wetland delineation .......................................................................................... 21

Figure 6-2: Vegetation indicators: A: Juncus effusus (Soft Rush); B: Agrostis lachnantha

(Bent Grass); C: Eragrostis gummiflua (Gum Grass); D: Andropogon huillensis (Large Silver

Andropogon); E: Utricularia sp. and F: Limosella aricana (Mudwort)). ................................. 23

Figure 6-3: Soil indicators (A and B: soil mottling in the permanent zone of the Weltevreden

Pan; C and D: E-horizon soil in the seasonal zone of the valley bottom system that is

indicative of the seasonal wetland and E: characteristic gleying) ........................................ 24

Figure 6-4: Radial plots of Eco-services provided by wetlands on site (A: valley bottom

without a channel; B: hillslope seep connected to the watercourse; C: hillslope seep

connected to a pan; D: isolated hillslope seep and E: pan / depression) ............................. 30

Figure 6-5: Examples of current impacts on wetlands on site (A: damming across a channel;

B: alien bushclumps in the catchment of a valley bottom wetland and C: cattle path through

an overgrazed pan) ............................................................................................................. 32

Figure 6-6: Present Ecological State and Ecological Importance and Sensitivity ................. 33

Figure 7-1: Mitigation hierarchy ........................................................................................... 34

Figure 10-2: Impacts Assessment ....................................................................................... 35

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Digby Wells Environmental v

LIST OF TABLES

Table 2-1: NFEPA wetland classification ranking criteria ....................................................... 8

Table 2-2: NFEPA wetlands for the Weltevreden site ............................................................ 9

Table 5-1: Impact scores and Present Ecological State categories used by WET-Health .... 15

Table 5-2: Criteria used for determining the EIS of wetlands ............................................... 16

Table 5-3: Impact Assessment methodology ....................................................................... 17

Table 6-1: Wetland units delineated on site ......................................................................... 19

Table 6-2: Plant species used as indicators of wetlands ..................................................... 22

Table 6-3: Descriptions of HGM units observed on site ....................................................... 25

Table 6-4: List and scoring of eco-services provided by HGM units on site ......................... 28

Table 7-1: Area of wetland anticipated to be lost to the proposed opencast mine ............... 34

Table 7-2: The details pertaining to the mitigation hierarchy for the project ......................... 40

LIST OF APPENDICES

Appendix A: CV’s of the Specialists

Appendix B: Wetland Delineation Methodology

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Digby Wells Environmental 1

1 Introduction

The general conservation status of freshwater ecosystems worldwide is poor and continues

to decline at a rapid rate, with rivers and wetlands among the most threatened of all

ecosystems (Vitousek et al., 1997, Revenga et al., 2000). According to Moyle and Williams

(1990) and Jensen et al. (1993) this decline is a result of severe alteration caused by human

activities. With an ever increasing human population as well as economic development, an

increase in the demand for water is inevitable, as well as an increase in pollution to

freshwater ecosystems. The sectors which are responsible for this are the domestic,

agricultural, recreational and industrial sectors as they all depend on fresh flowing water

(Roux et al., 1996).

According to Jungwirth et al. (2000) and Muhar et al. (2000) aquatic ecosystems are heavily

degraded on a global level by these human activities and impacts. As a result it is important

for both conservation and management of freshwater systems to determine which basic

processes, functions and structures make up the ecological integrity of these ecosystems. In

spite of the fact that conservation of biological diversity has been the main aim of

conservation biology, the phrase “biological integrity” has formed the cornerstone of all these

programs. The ability of a biological system to function and maintain itself in the face of

changes in environmental conditions is referred to as biological or biotic integrity (Angemeier

and Karr, 1994).

South Africa has a diverse assortment of natural resources which does not include water

(Ashton, 2007). One of the primary reasons for the scarcity of our water resources is that the

excessive human population growth and development has resulted in unbalancing the

availability of and state of water resources locally and on a global scale (Davies & Day,

1998). Water resources in South Africa are currently considered to be finite which suggests

that in South Africa as a result of the excessive use of water resources will result in a water

shortage that will progress into a water crisis unless the adequate management actions are

taken to address this area of concern (Davies & Day, 1998).

There have been some significant changes over the past few years to the priorities and

approaches to management of water resources in South Africa (Ashton et. al, 2005).

Culmination in the promulgation of the Water Services Act (WSA: Republic of South Africa,

1997) and the National Water Act (NWA: Republic of South Africa, 1998) may be attributed

to the process of reform of the policy on water resources and water services (Ashton et. al,

2005).

According to the National Water Act (Act 36 of 1998), a water resource is not only

considered to be the water that can be extracted from a system and utilized but the entire

water cycle. This includes evaporation, precipitation and entire aquatic ecosystem including

the physical or structural aquatic habitats, the water, the aquatic biota, and the physical,

chemical and ecological processes that link water, habitats and biota. The entire ecosystem

is acknowledged as a life support system by the National Water Act. According to van Wyk

et al. (2006) the “resource” is defined to include a water course, surface water, estuary and

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aquifer, on the understanding that a water course includes rivers and springs, the channels

in which the water flows regularly or intermittently, wetlands, lakes and dams into or from

which water flows, and where relevant, the banks and bed or the system.

Basic human needs, societal well-being and economic growth and development are

supported by river ecosystem goods and services. A range of processes which support

human well-being are included as ecosystem services such as the maintenance of water

quality, waste disposal as well as those services relating to recreational and spiritual needs

(van Wyk et al., 2006). The Act requires that sufficient water is to be reserved to maintain as

well as sustain the ecological functioning of the country’s aquatic ecosystems which include

rivers, wetlands, groundwater and estuarine systems. If the country’s water resources

continue to be abused and deteriorate, this will result in an unavoidable loss of key

ecosystem services that support social and economic development (Postel and Richter,

2003; Driver et al., 2005; MEA, 2005; Dudgeon et al., 2006; Dasgupta, 2007). The diverse

goods and services provided for by water resource are acknowledged by the National Water

Act. This ingrains the democratic principles necessary to safeguard equity in access to these

resources. The aim is that society should be able to use as well as protect an agreed upon

suite of goods and services derived from the water resource. The water law provides for an

integrated, adaptive process for water resource management.

The optimal use of natural resources for sustainable economic activity is essential in

developing countries (Howarth and Farber, 2002). Biodiversity is a vital component for

maintaining ecological processes and thus in ensuring sustainability of the ecosystem goods

and services which is vital for successful water resource management (MacKat et al., 2004)

South Africa’s National Biodiversity Strategy and Action Plan (DEAT, 2005) acknowledges

that there is cause for significant concern due to the declining status of ecosystems that

degradation of ecosystems leads to a reduction in ecosystem services. This may result in a

reduced capacity to generate clean water and a loss of food production due to land

degradation.

The overall framework for environmental governance in South Africa has been created by

South Africa’s Constitution (Act 108 of 1996) by establishing the right to an environment that

is not harmful to health and well-being, by balancing the right to have the environment

protected with rights to valid social and economic development and by allocating

environmental functions to a wide range of government agencies in all spheres and requiring

co-operation between government agencies and spheres of government (DEAT, 2005).

National legislation has been promulgated to govern national competencies, one of which is

water (National Water Act).

Therefore the approach adopted within South Africa by freshwater surface ecosystem

regulators to balance the use of aquatic ecosystems includes ascertaining the current state

and or availability of ecosystem resources, allocating ecological, social and or economic

values to the resource to enable the sustainable use and or protection of the resources. In

this study the surface aquatic ecosystems associated with the proposed Northern Coal

mining activity, consisting of the associated wetland areas as well as the Klein Komati River,

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have been addressed. The South African River Health Programme (RHP) primarily makes

use of biological indicators (e.g. fish communities, riparian vegetation, aquatic invertebrate

fauna) to assess the condition or health of river systems. These methodologies were

developed for lotic systems (rivers and streams) and are not applicable to lentic ecosystems

(dams, lakes, pans etc.). Due to the lentic nature of the system assessed, only a wetland

assessment was conducted. The delineation of the wetland areas was done in accordance

with the DWAF (2005) methodology.

Wetlands are highly susceptible to the degradation of quality and a reduction in quantity as a

result of anthropogenic resource use activities, (Mitsch and Gosselink, 1993; Brinson, 1993;

Bernaldez et al., 1993, Diederichs and Ellery, 2001) land-surface-development (Gibbs, 2000)

and landscape-management (Kotze and Breen, 1994; Whitlow, 1992) practices that alter

their hydrological regime impacting these systems (Winter and Llamas, 1993). Historically

wetlands have been perceived to be wastelands (Maltby, 1986) and this has resulted in the

exploitation, alteration and in many cases the complete destruction of these valuable

ecosystems, with an accompanying loss of associated ecosystem goods and services

(Begg, 1986). It is now acknowledged that these ecosystems perform functions making them

invaluable to the management of both water quantity and quality, and as a result wetlands

are regarded as integral components of catchment systems (Jewitt and Kotze, 2000;

Dickens et al., 2003).

The aim of the study is to delineate the associated wetland areas of the study area. The

following tasks were identified in order to meet the project objectives:

■ Conduct a desktop and field investigation of the wetlands within the study areas;

■ Assess, classify, delineate and map the identified wetlands;

■ Describe the general functions of the wetlands;

■ Determine the Present Ecological State (PES) and Ecological Importance and

Sensitivity

■ (EIS) of the wetlands on site; and

■ Provide a report with maps of wetlands, detailing all the information.

This report presents the approach adopted, the results of the approach as well as a

discussion of the significance and relevance of the determined results. Additionally,

management options have also been provided to protect and manage ecosystems and

areas of ecological importance.

1.1 Terms of Reference

Digby Wells & Associates (DWA) was appointed by Northern Coal (Pty) Ltd to undertake a

wetland study on the farm Weltevreden in the Belfast area, Mpumalanga. This study is for

the proposed opencast mining operation, inclusive of three opencast pits, intended for the

study area. Information generated from this survey would be used to delineate, classify and

map the wetlands at Weltevreden. A wetland assessment had already been completed by

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Digby Wells in 2008 and the primary objective of this study is to update the former report.

Studies that have previously been completed for the area and were used to update this

report include:

■ Pan Biodiversity Assessment of Weltevreden Pan. Digby Wells, 2014.

■ Wetland Delineation: Wetlands and aquatic systems associated with Weltevreden,

Belfast, Mpumalanga. Digby Wells, 2008.

The National Water Act 36 of 1998 is important in that it provides a framework to protect

water resources against over exploitation and to ensure that there is water for social and

economic development, human needs and to meet the needs of the aquatic environment.

The Act recognises both wetlands and rivers as water resources and are both protected

under the Act. This study addresses selected regulations and regulatory procedures of the

South Africa Departments of Water Affairs and Forestry and the Department of

Environmental Affairs and Tourism.

2 Study Area

The study area is situated in the Mpumalanga Province, in the Highlands Local Municipality

between the N4 and R33 roads. The site consists of maize fields, stands of Eucalyptus spp.,

pans and grasslands (Figure 2-1). Evidence of agricultural activities that took place on the

site (cattle grazing) is evident. A rocky area is present to the north of the pans.

Approximately 219 ha will be mined using open cast methods.

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Figure 2-1: Locality

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2.1 Drainage and Quaternary Catchments

The study area is situated within the Komati River quaternary catchment (X11D); which has

been allocated a Present Ecological State (PES) of ‘moderately modified’ (C). The affected

watercourse is the Klein Komati River which flows into the Komati River. Figure 2-2

represents the quaternary catchments for the Weltevreden site.

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Figure 2-2: Quaternary Catchments

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2.2 National Freshwater Ecosystem Priority Areas (NFEPA)

The National Freshwater Ecosystem Priority Areas (NFEPA) strategic spatial priorities for

conserving the country’s freshwater ecosystems and supporting sustainable use of water

resources were considered to evaluate the importance of the wetland areas located within

the Northern Coal mining project area (Nel et al. 2011).

Spatial layers (FEPA’s) used include the wetland classification and ranking. The identified

wetland areas play important functions such as the enhancement of water quality,

attenuation of floods and biodiversity support.

The NFEPA wetlands have been ranked in terms of importance in the conservation of

biodiversity. Table 2-1 below indicates the criteria which were considered for the ranking of

wetland areas. Three wetland units have been identified by NFEPA, as listed in Table 2-2

and represented in Figure 2-3. Both the Weltevreden pan and the northern seep have been

assigned an NFEPA ranking of two. This implies that these wetland units are (or are within

proximity to) important for the maintenance of biodiversity and may be regarded as

necessary habitat for an IUCN-listed threatened frog species, threatened waterbirds or other

important biodiversity features. The rank 6 wetland is not regarded to be as significant.

The identification of wetland and aquatic NFEPA’s takes place on a large scale and as a

result, not all wetland units present on a site are always identified.

Table 2-1: NFEPA wetland classification ranking criteria

Criteria Rank

Wetlands that intersect with a RAMSAR site. 1

Wetlands within 500 m of an IUCN threatened frog point locality; Wetlands within 500 m of a threatened waterbird point locality; Wetlands (excluding dams) with the majority of their area within a sub-quaternary catchment that has sightings or breeding areas for threatened Wattled Cranes, Grey Crowned Cranes and Blue Cranes; Wetlands (excluding dams) within a sub-quaternary catchment identified by experts at the regional review workshops as containing wetlands of exceptional Biodiversity importance, with valid reasons documented; and Wetlands (excluding dams) within a sub-quaternary catchment identified by experts at the regional review workshops as containing wetlands that are good, intact examples from which to choose.

2

Wetlands (excluding dams) within a sub-quaternary catchment identified by experts at the regional review workshops as containing wetlands of biodiversity importance, but with no valid reasons documented.

3

Wetlands (excluding dams) in A or B condition AND associated with more than three other wetlands (both riverine and non-riverine wetlands were assessed for this criterion); and Wetlands in C condition AND associated with more than three other wetlands (both riverine and non-riverine wetlands were assessed for this criterion).

4

Wetlands (excluding dams) within a sub-quaternary catchment identified by experts at the regional review workshops as containing Impacted Working for Wetland sites.

5

Any other wetland (excluding dams). 6

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Table 2-2: NFEPA wetlands for the Weltevreden site

Wetland Unit HGM Unit NFEPA rank

Bench, Depression Weltevreden Depression / Pan 2

Slope, Seep Seep 2

Slope, Seep Seep 6

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Figure 2-3: NFEPA wetlands associated with the study area

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2.3 Mpumalanga Conservation Plan (C-Plan)

The Mpumalanga Biodiversity Conservation Plan (MBCP) is a plan developed conjointly by

the Mpumalanga Tourism and Parks Agency (MTPA) and Department of Agriculture and

land Administration (DALA) to guide conservation and land-use decisions in the province in

order to support sustainable development. The MTPA recognises that wetlands are

specialised systems that perform ecological functions that are crucial for human and

environmental welfare. Figure 2-4 indicates that the Mpumalanga C-plan does not recognise

any areas that are critical or irreplaceable in the study area and that the majority of wetlands

are classified as natural.

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Figure 2-4: Mpumalanga C-Plan

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3 Expertise of the Specialist

The Digby Wells Biophysical Department is comprised of a team of qualified and

experienced environmental scientists. Members specialise in their respective fields and the

senior members are registered as Professional Natural Scientists. Appendix A lists the

detailed Curriculum Vitae (CV) for specialists involved in this study.

4 Aims and Objectives

The aim for this component of the study was to delineate the associated wetland areas. The

following tasks were identified in order to meet the project objectives:

■ Conduct a desktop and field investigation of the wetlands within the study areas;

■ Assess, classify, delineate and map the identified wetlands;

■ Describe the general functions of the wetlands;

■ Determine the Present Ecological State and Ecological Importance and Sensitivity of

the wetlands on site; and

■ Provide a report with maps of wetlands, detailing all the information.

5 Methodology

5.1 Wetland Identification and delineation

Maps were generated from 1:50 000 topographic maps and aerial photographs, onto which

the wetland areas were identified and preliminary wetland boundaries were delineated at the

desktop level. The identified wetlands were temporarily classified according to their Hydro-

geomorphic (HGM) Unit determinants based on modification of the system proposed by

Brinson (1993), and modified for use by Marneweck and Batchelor (2002) and subsequently

revised by Kotze et al. (2004). The HGM Unit system of classification focuses on the hydro-

geomorphic setting of wetlands which incorporates geomorphology; water movement into,

through and out of the wetland; and landscape / topographic setting. Once wetlands have

been identified, they are categorised into HGM Units as in Figure 5-1. HGM Units are then

assessed individually for habitat integrity.

The initial site investigation was undertaken in November 2013 for orientation and to assess

wetland integrity during the wet-season. This time of year is ideal for field investigations, as it

coincides with the flowering-time of many of the plant species that occur in wetlands and

animals are also most active. This also coincides with the time recommended by the

Mpumalanga Parks and Tourism Agency (MTPA). An additional site visit was conducted in

April 2014 in order to confirm the boundaries of wetlands on site. The site visit included a

concise evaluation of the current impacts on the wetland habitat on site, as well as the

features that contribute to ecological integrity and functionality.

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Figure 5-1: Wetland HGM Units (modified from Brinson 1993; Kotze 1999 and

Marneweck and Batchelor 2002)

Floodplain

Valley bottom areas with a well-defined stream channel

stream channel, gently sloped and characterised by floodplain

features such as oxbow depression and natural levees and the

alluvial (by water) transport and deposition of sediment ,

usually leading to a net accumulation of sediment. Water

inputs from main channel (when channel banks overspill) and

from adjacent slopes.

Valley bottom

with a channel

Valley bottom areas with a well-defined stream channel but

lacking characteristic floodplain features. May be gently sloped

and characterized by the net accumulation of alluvial deposits

or may have steeper slopes and be characterised by the net

loss of sediment. Water inputs from the main channel (when

channel banks overspill) and from adjacent slopes.

Valley bottom

without a

channel

Valley bottom areas with no clearly defined stream channel,

usually gently sloped and characterised by alluvial sediment

deposition, generally leading to a net accumulation of

sediment. Water inputs mainly from the channel entering the

wetland and also from adjacent slopes.

Hillslope

seepage linked

to a stream

channel

Slopes on hillsides, which are characterised by colluvial

(transported by gravity) movement of materials. Water inputs

are mainly from sub-surface flow and outflow is usually via a

well-defined stream channel connecting the area directly to a

stream channel.

Isolated

hillslope

seepage

Slopes on hillsides that are characterised by colluvial transport

(transported by gravity) movement of materials. Water inputs

are from sub-surface flow and outflow either very limited or

through diffuse sub-surface flow but with no direct link to a

surface water channel.

Pan/Depression

A basin-shaped area with a closed elevation contour that

allows for the accumulation of surface water (ie. It is inward

draining). It may also receive subsurface water. An outlet is

usually absent and so this type of wetland is usually isolated

from the stream network.

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5.2 Wetland Delineation

In accordance with the DWAF guidelines (DWAF 2005) the wetland delineation procedure

considers four attributes to determine the limitations of the wetland. These attributes are

discussed according to the DWAF guidelines in further detail later on in this section. Further

descriptions on the four attributes are presented in Appendix B. The four attributes are:

■ Terrain Unit Indicator – helps to identify those parts of the landscape where wetlands

are more likely to occur;

■ Soil Form Indicator – identifies the soil forms, which are associated with prolonged

and frequent saturation;

■ Soil Wetness Indicator – identifies the morphological “signatures” developed in the

soil profile as a result of prolonged and frequent saturation; and

■ Vegetation Indicator – identifies hydrophilic vegetation associated with frequently

saturated soils.

In accordance with the definition of a wetland in the NWA, vegetation is the primary indicator

of a wetland, which must be present under normal circumstances; however, the soil wetness

indicator tends to be the most important in practice. The remaining three indicators are then

used in a confirmatory role. The reason for this, is that the response of vegetation to

changes in the soil moisture regime or management are relatively quick and may be

transformed, whereas the morphological indicators in the soil are significantly more

permanent and will hold the indications of frequent and prolonged saturation long after a

wetland has been drained (perhaps several centuries) (DWAF 2005).

5.3 Wetland Ecological Health Assessment

A PES analysis was conducted to establish baseline integrity (health) for the associated

wetlands. In order to determine the integrity (health) of the characterized HGM units for the

project area, the WET-Health tool was applied. According to Macfarlane et al. (2007) the

health of a wetland can be defined as a measure of the deviation of wetland structure and

function from the wetland’s natural reference condition. The health assessment attempts to

evaluate the hydrological, geomorphological and vegetation health in three separate

modules in order to attempt to estimate similarity to or deviation from natural conditions. The

Present Ecological State (PES) is determined according to Table 5-1.

Table 5-1: Impact scores and Present Ecological State categories used by WET-Health

Description Combined Impact Score

PES Category

Unmodified, natural. 0-0.9 A

Largely natural with few modifications. A slight change in ecosystem processes is discernible and a small loss of natural habitats and biota has

1-1.9 B

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Description Combined Impact Score

PES Category

taken place.

Moderately modified. A moderate change in ecosystem processes and loss of natural habitats has taken place but the natural habitat remains predominantly intact.

2-3.9 C

Largely modified. A large change in ecosystem processes and loss of natural habitat and biota has occurred.

4-5.9 D

The change in ecosystem processes and loss of natural habitat and biota is great but some remaining natural habitat features are still recognisable.

6-7.9 E

Modifications have reached a critical level and ecosystem processes have been modified completely with an almost complete loss of natural habitat and biota.

8-10 F

5.4 Wetland Ecological Importance and Functionality Assessment

In order to assess the importance of wetlands identified on site from an ecological

perspective, taking into account aspects related solely to the maintenance of ecological

diversity and functionality, the EIS tool was used. For this methodology, a series of

determinants are assessed using a ranking scale of 0-4 (Table 5-2), from which the median

of each determinant is used to allocate an ecological management class.

Table 5-2: Criteria used for determining the EIS of wetlands

Primary determinants

1. Rare & Endangered Species

2. Populations of Unique Species

3. Species/taxon Richness

4. Diversity of Habitat Types or Features

5 Migration route/breeding and feeding site for wetland species

6. Sensitivity to Changes in the Natural Hydrological Regime

7. Sensitivity to Water Quality Changes

8. Flood Storage, Energy Dissipation & Particulate/Element Removal

Modifying determinants

9. Protected Status

10. Ecological Integrity

5.5 Wetland Functional Assessment

The onsite wetlands were grouped according to homogeneity and assessed utilising the

functional assessment technique, WET-EcoServices, developed by Kotze et al. (2007) to

provide an indication of the benefits and services. As a result of this, scores are not wetland

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area specific but do however provide an indication of the ecological services offered by the

different wetland systems as a whole for this project area.

5.6 Impact Assessment

The impacts of the development and operation of the proposed underground coal mining

project on the receiving wetlands areas within the project area were assessed at different

stages of the development of the mine according to the methodology indicated in Table 5-3.

A clearly defined rating scale is used to assess each impact in terms of severity, spatial

extent and duration (which determines the consequence) and in terms of the frequency of

the activity and the frequency of the related impact (which determines the likelihood of

occurrence). The overall impact significance, is then determined via a significance rating

matrix (Table 5-3) utilising the scores obtained for consequence and likelihood of

occurrence, in order to assign a final impact rating.

Table 5-3: Impact Assessment methodology

Rating Severity Spatial scale Duration Probability

7

Very significant

impact on the

environment.

Irreparable damage

to highly valued

species, habitat or

eco system.

Persistent severe

damage.

International

The effect will

occur across

international

borders

Permanent: No

Mitigation

No mitigation

measures of

natural process

will reduce the

impact after

implementation.

Certain/ Definite.

The impact will occur

regardless of the

implementation of any

preventative or corrective

actions.

6

Significant impact on

highly valued species,

habitat or ecosystem.

National

Will affect the

entire country

Permanent:

Mitigation

Mitigation

measures of

natural process

will reduce the

impact.

Almost certain/Highly

probable

It is most likely that the impact

will occur.

5

Very serious, long-

term environmental

impairment of

ecosystem function

that may take several

years to rehabilitate

Province/

Region

Will affect the

entire

province or

region

Project Life

The impact will

cease after the

operational life

span of the

project.

Likely

The impact may occur.

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Rating Severity Spatial scale Duration Probability

4

Serious medium term

environmental effects.

Environmental

damage can be

reversed in less than

a year

Municipal

Area

Will affect the

whole

municipal

area

Long term

6-15 years

Probable

Has occurred here or

elsewhere and could

therefore occur.

3

Moderate, short-term

effects but not

affecting ecosystem

functions.

Rehabilitation

requires intervention

of external specialists

and can be done in

less than a month.

Local

Local

extending

only as far as

the

development

site area

Medium term

1-5 years

Unlikely

Has not happened yet but

could happen once in the

lifetime of the project,

therefore there is a possibility

that the impact will occur.

2

Minor effects on

biological or physical

environment.

Environmental

damage can be

rehabilitated internally

with/ without help of

external consultants.

Limited

Limited to the

site and its

immediate

surroundings

Short term

Less than 1 year

Rare/ improbable

Conceivable, but only in

extreme circumstances and/

or has not happened during

lifetime of the project but has

happened elsewhere. The

possibility of the impact

materialising is very low as a

result of design, historic

experience or implementation

of adequate mitigation

measures

1

Limited damage to

minimal area of low

significance, (e.g. ad

hoc spills within plant

area). Will have no

impact on the

environment.

Very limited

Limited to

specific

isolated parts

of the site.

Immediate

Less than 1

month

Highly unlikely/None

Expected never to happen.

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6 Results

6.1 Wetland delineation

The wetland delineation was completed using the four wetland indicators: terrain indicator,

soil form, soil wetness characteristics and wetland vegetation. Section 6.1.1 to 6.1.3

describes the presence of these four indicators on site. Three major HGM units were

recorded on site, namely: valley bottom wetlands without a channel, hillslope seeps and pan

/ depressions. The hillslope seeps were either isolated as small patches along slopes, or

were linked to other HGM units. Table 6-1 represents the areas of HGM units recorded on

site and Figure 6-1 shows their distribution. A total of 160.3 ha of wetland habitat were

delineated on site, largely made up of hillslope seeps (65.7 ha).

Table 6-1: Wetland units delineated on site

HGM Unit Area (ha) Proportion of total wetlands

on site (%)

Valley Bottom without a

Channel

41.5 25.9

Hillslope seepage wetlands

connected to watercourses

65.7 41

Hillslope seepage wetlands

connected to pans

2.9 1.8

Isolated hillslope seepage

wetlands

48.8 30.4

Pans 1.4 0.9

Total 160.3 100

A 100m buffer has been assigned for surface infrastructure and the opencast pits, in

accordance with the NWA (Act 36 of 1998). The buffer zones are a requirement in order to

facilitate the protection of the delineated wetland areas within the project area. The purpose

of the establishment of buffer zones is to minimise the anthropogenic impacts associated

with the proposed development on the receiving water resources. A buffer zone is defined

as:

“the strips of undeveloped, typically vegetated land (composed in many cases of riparian

habitat or terrestrial plant communities) which separate development or adjacent land uses

from aquatic ecosystems (rivers and wetlands).”

A number of explanations have been provided for the establishment of buffer zones, some of

the reasons are listed below:

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■ Reducing the impacts of adjacent land uses on water resource quality and the

associated biodiversity, and;

■ Sustaining or improving the ability of the water resources to provide goods and

services to the current and future water end users within the catchment area.

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Figure 6-1: Wetland delineation

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6.1.1 Vegetation Indicator

Typha capensis (Common Bulrush), a common species of the permanent wetland, colonised

channels of the valley bottom type wetlands and formed mono-specific stands in certain

areas with the exception of the alien forb: Verbena bonariensis (Common Vervain). In

addition, Utricularia sp. and Limosella africana were found in the permanently wet zone.

Species that are associated with the seasonal and temporary zones were of particular

significance as the edges of where these occur were marked to determine the edge of

wetlands. Table 6-2 lists the plant species that were used as indicators of wet conditions on

site and Figure 6-2 represents examples of these. Two plant Species of Special Concern

(SSC) were recorded in wetland habitat (see Flora and Fauna Report, Digby Wells 2014),

namely: Boophone disticha (Tumbleweed) and Eucomis autumnalis (Pineapple Flower).

Table 6-2: Plant species used as indicators of wetlands

Family Species Common Name Description

Cyperaceae

Cyperus esculentus Yellow Nut Sedge Associated with streams of the valley bottom systems, this species is an indicator of seasonal wetland conditions.

Cyperus longus Waterbiesie Associated with streams of the valley bottom systems, this species is an indicator of the permanent zone.

Schoenoplectus corymbosus

This species was found on the edge of open water of the valley bottom systems.

Juncaceae

Juncus effusus Soft Rush This widespread species had colonised the ephemeral depression on site. J. effusus can be a native invader where overgrazing has taken place, as is the case at Weltevreden pan.

Poaceae

Agrostis lachnantha Bent Grass This facultative hydrophyte was found in hillslope seep wetlands, linked to the channel, in association with Imperata cyclindrica.

Andropogon eucomus Snowflake Grass A facultative hydrophytic grass that is found in the temporary zone of wetlands associated with hillslope seeps linked to the channel.

Andropogon huillensis Large Silver Andropogon

A. huillensis grows in seasonal to permanent wetland zones and was found in hillslope seeps linked to the channel.

Eragrostis gummiflua Gum Grass This facultative hydrophyte is found in disturbed areas of rocky grassland and also on the edges of wetlands.

Imperata cylindrica Cotton Wool I. cylindrica is a characteristic

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Grass feature of hillslope seeps and formed monospecific patches in isolated seeps on site. This grass turns a deep red during winter and is typically easy to distinguish from the dry Highveld grassland surrounds.

Typhaceae

Typha capensis Common Bulrush The most dominant bulrush in South Africa, this species is typical of the permanent wetland zone where shallow water is found throughout the year.

Figure 6-2: Vegetation indicators: A: Juncus effusus (Soft Rush); B: Agrostis

lachnantha (Bent Grass); C: Eragrostis gummiflua (Gum Grass); D: Andropogon

huillensis (Large Silver Andropogon); E: Utricularia sp. and F: Limosella aricana

(Mudwort)).

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6.1.2 Soil Indicator

Soil samples were taken (where possible) as transects across wetlands in order to

determine boundaries. Soil forms that are characteristic of wetlands and were present in on

site were: Dresden (Dr1), Longlands (Lo1), and Katspruit (Ka) (Digby Wells Soils Report,

2009). These soil types, as well as the E-horizon, are recognised by DWAF (2003) as

wetland soils. With regard to soil wetness features, mottling and characteristic gleyed G

horizon were used as indicators. Figure 6-3 shows examples of soils associated with

wetlands on site.

Figure 6-3: Soil indicators (A and B: soil mottling in the permanent zone of the

Weltevreden Pan; C and D: E-horizon soil in the seasonal zone of the valley bottom

system that is indicative of the seasonal wetland and E: characteristic gleying)

6.1.3 Terrain Indicator

As aforementioned, the landscape of the study area is studied on a desktop level prior to

field investigation in order to determine potential wetlands on site. Aspects of elevation and

slope are identified and later ground-truthed in the field. Isolated hillslope seeps and some

pan / depression wetlands do not necessarily occur at the lowest point in the landscape and

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in such cases, soil and vegetation indicators are used to confirm their presence. Wetlands

identified are classified into HGM units based on geomorphology and hydrology. Table 6-3

provides descriptions of the HGM units that are present on site.

Table 6-3: Descriptions of HGM units observed on site

Wetland HGM Unit

Descriptions

Pan

/D

ep

ressio

n

Pans are shallow ephemeral

systems and generally occur over

shales and unconsolidated

surficial sandstones in South

Africa (Allan et al. 1995). Their

formation is dependent on a

number of factors, including

climate, geological susceptibility,

disturbance to the surface via

animals, salt-weathering, a lack of

integrated drainage systems and

deflation processes (Goudie and

Thomas 1985). They are inward

draining systems and as a result,

their catchment is regarded as sensitive.

The Wetevreden pan was fed primarily by surface water and was characterised by a narrow

catchment and an absence of seeps leading into it.

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Vall

ey b

ott

om

wit

ho

ut

a c

han

nel

The valley bottom wetlands

without channels are located at

the lowest position in a

landscape where the water

drained from the local slopes

accumulate. Water expressed in

the hillslope seepage wetlands

may also drain towards the

valley bottom wetlands. These

wetland systems play important

functions such as sediment

trapping, flood attenuation and

nutrient-cycling. The valley

bottom without a channel

wetland on site receives

extensive amounts of sediment and flow from the surrounding cultivated slopes. This allows

an opportunity for contact between solute-laiden water and the wetland vegetation, thus

providing an opportunity for flood and contaminant (nutrients, pesticides, herbicides)

attenuation. Extensive areas of these wetlands remain saturated as stream channel input is

spread diffusely across the valley bottom, even at low flows (Kotze et al., 2007). These

wetlands also tend to have a high organic content. Facultative wetland indicator plant

species, comprising a mixture of grasses and sedges are evident as longitudinal bands within

a relatively narrow zone along the valley bottoms. Facultative wetland plant species usually

grow in wetlands (67-99% of occurrences) but occasionally are found in non-wetland areas.

Lateral seep zones form part of the adjacent hillslope seepage wetlands, this is a

characteristic for all the valley bottom wetlands. The primary drivers for these systems, owing

to the shallow gradients along the valley bottoms are diffuse horizontal surface flow and

interflow. There is generally a clear distinction in the transition in the vegetation structure

between the mixed grass-sedge meadow zones that characterise these wetlands to the more

intermittently wet grassland habitats associated with the adjacent hillslope seepage wetlands

(Kotze et al., 2007).

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Seep

ag

e w

etl

an

d

Seepage wetlands are usually

associated with a perched

groundwater table, where

precipitation that occurs within

the greater catchment is

temporarily stored within the soil

profile as a result of impervious

strata in the soil profile. The

impervious strata within the soil

profile is normally made up of an

unweathered parent material or

swelling clays typically

associated with granites,

sandstones or shales. Hillslope

seepage wetlands are expressed were the soil profile is shallow enough such that impervious

layer and the water stored within the soil profile are expressed on the surface. The soils in the

area must be waterlogged long enough for oxygen to be depleted through a chemical

process of reduction which results in the presence of radoximorphic features in the soil.

Hillslope seepage wetlands are created and maintained by infiltration processes that occur in

the surrounding non-wetland areas within the catchment. Hillslope seepage wetlands

connected to watercourses are wetland systems which are directly linked on the surface to

watercourses. This type of system typically contributes to flow in the watercourses, even if

this contribution is only on a seasonal basis.

Hillslope seeps may be isolated (as frequently observed on the Weltevreden site) or linked to

a stream channel or depression. Isolated hillslope seeps identified on site were colonised by

Imperata cylindrica (Cottom Wool Grass).

6.2 Wetland Functionality

Extensive literature searches have revealed that very few practitioners have quantified the

benefits of wetland functionality. In addition to this, it appears likely that the functions of the

wetlands are variable depending on the characteristics of the wetlands and landscape.

The general features of the wetlands were assessed in terms of functioning and the overall

importance of each hydrogeomorphic unit was then determined at a landscape level. The

level of functioning supplied by each of the hydrogeomorphic units for various ecological

services is presented in Table 6-4. The results from the “WET-EcoServices” tool are

presented below in Figure 6-4.

HGM Units were rated according to the following scale:

■ <0.5 Low

■ 0.5-1.2 Moderately Low

■ 1.3-2.0 Intermediate

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■ 2.1-2.8 High

■ >2.8 Very High

The hillslope seepage wetlands connected to the watercourse, isolated hillslope seepage

wetlands and valley bottom wetlands scored moderately high for water quality enhancement;

including sediment trapping, phosphate trapping, nutrient processing and toxicant removal.

Water quality enhancement is regarded as the most significant eco-service provided by

wetlands on site. It is important to consider the proximity of the agricultural land to the

wetlands and the use of the wetlands by livestock. Additionally, the proposed mining

activities may limit the quantity of water recharging the wetland areas as well as impact on

the quality of available water, thus it may be assumed that the functioning of the wetland

areas to offer services in terms of water quality improvement may become more important

as mining operations progress.

As a result of the reduction in quantity of water recharging wetland areas, it may be assumed

that certain wetland areas will be lost. Regardless of this, it is imperative that the loss of

wetlands area is minimal so as to maintain the ecological services offered. The valley bottom

wetlands receive water inputs from adjacent slopes via runoff and interflow from the hillslope

seeps. Hillslope seeps receive water from groundwater sources through perched aquifers.

As a result of the proposed opencast mining activities, there will be alterations in

underground water dynamics, as well as the removal of surface drainage areas. This in turn

will limit the quantity of water leading to the wetlands downstream. Pans receive water inputs

from runoff from the surrounding catchment area and lateral seepage from adjacent hillslope

seeps. As a result of this, it is highly recommended that wetlands downstream of the mining

operation be recharged artificially.

Table 6-4: List and scoring of eco-services provided by HGM units on site

Summary Sheet Valley bottom

without a

channel

Hillslope

seep

connected to

pan

Hillslope seep

connected to

watercourse

Isolated

hillslope seep

Pans

Overall score Overall score Overall score Overall score Overall score

Flood attenuation 2.3 1.9 2.2 1.8 1.8

Stream – flow

regulation

3.2 2.2 2.4 1.4 2.0

Sediment trapping 2.5 1.9 3.1 2.5 1.9

Phosphate trapping 3.2 1.9 3.0 2.5 2.6

Nitrate removal 3.3 2.6 2.8 2.5 2.6

Toxicant removal 3.2 2.3 3.1 2.8 2.3

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Erosion control 2.0 1.8 2.5 2.2 0.8

Carbon storage 2.0 1.7 2.3 2.0 1.3

Maintenance of

biodiversity

2.3 2.4 1.7 1.6 2.7

Water supply for

human use

2.7 1.4 1.2 0.9 2.0

Natural Resources 1.2 0.8 0.8 0.8 1.0

Cultivated foods 0.2 0.8 0.8 0.8 0.2

Cultural significance 0.0 0.0 0.0 0.0 0.0

Tourism and

recreation

1.3 0.6 0.7 0.9 1.1

Education and

research

1.8 1.8 1.3 1.0 1.8

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Figure 6-4: Radial plots of Eco-services provided by wetlands on site (A: valley

bottom without a channel; B: hillslope seep connected to the watercourse; C:

hillslope seep connected to a pan; D: isolated hillslope seep and E: pan / depression)

6.3 Wetland Present Ecological State (PES)

All of the wetlands within the study area have been modified to some extent with 76.3% of

the wetlands being moderately modified (PES C) and 23.7% regarded as largely modified

(PES D). Figure 6-5 represents examples of impacts on wetlands on site.

The general features of the identified wetland units within the project were assessed in terms

of impacts on the integrity of these systems. The identified impacts are associated with

activities such as livestock farming, crop cultivation (Maize) and damming. Damming is

regarded as the major impact on site. Some of the impacts identified within the project area

during the site investigations include:

■ Overgrazing and trampling by livestock: This was particularly observed in the pan,

where paths had forms due to livestock trampling. Further to this, Juncus effusus had

become dominant as other species present had been overgrazed. Trampling of

vegetation results in a decrease in surface roughness; which in turn increases the rate

of infiltration and can also promote erosional processes;

■ Eutrophication from the use of pesticides and fertilisers: Evidence of this was

observed in valley bottom wetlands; where colonies of Utricularia sp. had begun to

form dense mats. Although the current scenario is not regarded as a major impact,

mat-forming water plants may establish if the nutrient load of the wetlands increases

and owing to the exponential growth habits of these plants, flow may be impeded;

■ Damming: 5.44% of valley bottom wetlands on site were made up of dams. The

result is shortening and diversion of natural channels as well as the trapping of

sediment. Sediment trapped in dams is critical for the maintenance of habitats and

physical processes downstream. Furthermore, when the sediment load downstream is

not replenished, erosional processes are promoted and the stream or river may

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become deeply incised. Damming may also hamper the transfer of genetic material

through streams and rivers in the form of fish and invertebrates and

■ Local farm roads crossing wetlands: This causes compaction of sediments which

hampers water flow through the wetlands.

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Figure 6-5 represents examples of impacts on hydrology, geomorphology and vegetation.

Figure 6-5: Examples of current impacts on wetlands on site (A: damming across a

channel; B: alien bushclumps in the catchment of a valley bottom wetland and C:

cattle path through an overgrazed pan)

6.4 Wetland Ecological Importance and Sensitivity (EIS)

The highest ecological importance and sensitivity scores (rated as C – moderate) are

associated with approximately 60% of the wetlands within the study area. These have the

highest EIS scores predominantly as a result of their functioning to retain water and support

adjacent wetland areas through interflow seepage. These wetland areas are considered to

be ecologically important and sensitive on a provincial or local scale. The biodiversity of

these wetland areas are not usually sensitive to flow and habitat modifications and in

addition to this, these wetland areas play a small role in moderating the quantity and quality

of water of major rivers. Approximately 40% of all the wetlands within the study area have

been rated low to marginal (rated as D) and these areas are no longer ecologically important

and sensitive at any scale. The reason being, these areas are currently being disturbed and

functioning altered through agricultural practices as well as with the destruction of wetland

areas by road and drainage channel construction.

Figure 6-6 represents both the PES and EIS of the identified wetlands on site.

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Figure 6-6: Present Ecological State and Ecological Importance and Sensitivity

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7 Impacts Assessment

As aforementioned in Section 5.6, the impacts of the proposed opencast mine will be

assessed using a standard rating table. The general approach for impacts assessment is to

adhere to the mitigation hierarchy, as represented in Figure 7-1. The aim is to strive to avoid

damage or loss of ecosystems and services that they provide and where they cannot be

avoided, to reduce and mitigate impacts (DEA, 2013). Offsets to compensate for loss of

habitat are regarded as a last resort, after all efforts have been made to avoid, reduce and

mitigate. Developments related to the proposed opencast mine to consider for the impacts

assessment include: opencast pits, Pollution Control Dams (PCD’s), diesel storage tank,

coal stockpile, haul road and additional mining infrastructure.

Figure 7-1: Mitigation hierarchy

The proposed mine plan, as represented will result in loss of 57.51 ha of wetland habitat,

primarily of hillslope seeps. The pan / depression wetland and the 100m buffer around it

have been excluded from the mine plan in order to avoid impacts on this wetland. Impacts

on the valley bottom wetland have been avoided as far as possible but seeps leading to the

wetland will be lost.

Figure 7-2 represents the area of wetland that coincides with the proposed opencast pits.

Table 7-1: Area of wetland anticipated to be lost to the proposed opencast mine

HGM unit Areas anticipated to be lost (ha)

Hillslope seepage connected to water course 34.71

Isolated hillslope seepage 22.56

Valley bottom without a channel 0.24

Total 57.51

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Figure 7-2: Impacts Assessment

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7.1 Issue 1: Loss of wetland area

A loss of hillslope seep wetland, leading to the valley bottom system is expected due to

opencast mining. Owing to the fact that the valley bottom systems are fed via groundwater

linkages, as well as surface water, the loss of aquifer-driven hillslope seeps will impact on

hydrology of these wetlands. The following impacts are expected to result from the direct

loss of wetland areas:

■ Impact 1: Loss of hillslope seeps

■ Impact 2: Loss of valley bottom systems

7.1.1 Impact 1 - Loss of hillslope seeps

Loss of seeps leading to wetlands, as aforementioned, will result in a loss of a water input

into valley bottom wetlands. As a consequence the valley bottom wetlands may reduce in

area. Although wetlands on site are regarded to be in a poor ecological condition, the loss of

these systems will remove the potential for any opportunities to improve their ecological

status at all.

Loss of wetlands will also reduce the area available for waterbirds that may utilise wetlands,

such as Grey Heron (Ardea cinerea) and Purple Heron (Ardea purpurea) (See Flora and

Fauna Report, Digby Wells 2014) as well as other wetland-dependant fauna such as

amphibians. Clearing of vegetation will result in loss of wetland plants and potentially SSC.

The proposed haul road and mining infrastructure currently transects the hillslope seepage

area to the south of the study area. The opencast mining operations will cause an

interruption to both ground and surface water dynamics and so it may be assumed that this

isolated hillslope seepage wetland to the south of the opencast mining area will be lost. In

spite of hillslope seepage areas normally being associated with groundwater discharges,

flow through may be supplemented by surface water contributions. In addition to this, these

units contribute to some surface flow attenuation. As a result of this, any unnecessary

destruction of the wetland area to the south of the mining activities should be avoided as

these wetlands still provide ecological functions such as water quality enhancement.

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7.1.2 Impact 2 - Loss of Valley Bottom Wetlands

Only 0.24 ha of valley bottom wetland is anticipated to be lost. The impacts on hydrology

and geomorphology are regarded as minimal.

Proposed Mitigation

There is no mitigation for loss of wetland habitat. It is highly recommended that the 100m

buffer be implemented for all wetland areas in order to reduce the potential impact.

Issue 1 Loss of habitat

Parameters Severity Spatial

scale

Duration Probability Significance

Impact 1 Loss of hillslope seeps

Pre- Mitigation Serious (4) Local (3) Permanent

(6)

Certain (7) Medium-High

(80)

Post-

Mitigation

No mitigation

Impact 2 Loss of valley bottom wetlands

Pre-Mitigation Minor (2) Local (3) Permanent

(6)

Highly

Probable (6)

Medium – Low

(66)

Post-

Mitigation

No Mitigation

7.2 Issue 2: Loss of wetland integrity and functionality

Although wetlands on site are not in a pristine condition, their ecological integrity and

functionality should be preserved and, if possible, improved. Failure to responsibly manage

polluted water and potentially hazardous substances on site will result in contamination of

water resources. Global research has place much focus on the treatment of water that has

been polluted by hydrocarbons and heavy metals related to mining (Wang et al. 2011) by

using technologies such as bioremediation and phytoremediation to remove contaminants.

The following impacts on wetland integrity and functionality are expected to occur:

7.2.1 Impact 3: Chemical contamination of surface water

Contamination of wetland areas with waste water from the coal mine area will result in the

loss of biodiversity, especially of very sensitive species. The severity of the loss of

biodiversity as a result of water contamination is regarded as significant due to the

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cumulative loss of wetland areas and the associated biodiversity within the region. The

potential of the impact being imposed onto the system as a result of the operation of the

mine is likely.

Proposed Mitigation

The mine should implement measures to separate contaminated mine water from clean rain

water to ensure that the contaminated water is contained and does not spill into the

surrounding wetland areas therefore impacting on their integrity.

The establishment of vegetated buffer strips must be constructed to function as a protective

barrier between the dirty water containment structures and the delineated wetland areas in

order to protect the integrity of wetlands. The vegetated buffer strips will function as filters

that intercept overland spill overs, trap sediments and other contaminants, reduce overland

flow velocities thus enhancing sedimentation and infiltration. In addition, the overflow of

contaminated water into the surrounding wetland areas should be prevented at all costs.

Diesel storage tanks should be bunded and or placed in sunken catchpits with bunded area

adequately lined and covered with loose sand that is large enough to contain a significant

spill, should it occur. Any possible spillage must be returned to the source via vertical

pumps. In the unlikely event of any spillages outside bunded areas, as well as contaminated

storm-water, flow to an emergency storage dam, for recycling back into the process.

Furthermore, all bunded areas must be designed to contain a minimum of 150% of any tank

volume inside its perimeter, in case of a failure of such a tank. Additionally, it is

recommended that the placement of the tank be in the same area suggested for the mining

infrastructure.

Impact 2 Loss of wetland integrity and functionality

Parameters Severity Spatial

scale

Duration Probability Significance

Issue 3 Chemical contamination of surface water

Pre- Mitigation Very

significant

(7)

Local (3) Permanent

(7)

Certain (7) Medium-High

(110)

Post-

Mitigation

Minor (2) Local (3) Immediate

(1)

Unlikely (3) Low (15)

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7.3 Cumulative Impacts

Due to the inappropriate management of water resources in the Komati River catchment, the

PES has been moderately modified. A major anticipated impact on the greater wetland

catchment is water contamination from mining activities. It is imperative that water

contamination is avoided at all costs, in valley bottom systems specifically; as these link up

to the greater stream network and may cause further degradation to the catchment. Misuse

of water resources due to mining has been observed in the Olifants catchment, where water

quality has undergone severe degradation.

The cumulative impact of the proposed opencast mine is regarded as moderate, as the

study area is not regarded as particularly significant from an ecological perspective. Owing

to a history or poor land management, the natural habitat on site has been transformed.

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7.4 Impact mitigation hierarchy

The mitigation hierarchy process has been considered for this project and the details

pertaining to the relevant sections and the associated recommendations are presented in

Table 7-2.

Table 7-2: The details pertaining to the mitigation hierarchy for the project

Stage Description

Avoid When possible wetland areas have been avoided. This processes resulted in

the mine plan being altered so that selected wetland areas can be avoided.

Areas that were allocated a poor EIS or PES score were included into the

mine plan, with more sensitive areas being excluded. In addition to this, where

possible existing infrastructure such as roads have been included into the

mine design and selected infrastructure such as the PCDs and site offices

have also been placed outside of the wetland areas.

Minimise Realistically there is no mitigation for the mining (opencast) of wetlands, these

impacts would have to be offset. Where impacts could be minimised,

mitigation measures have been prescribed.

Rehabilitate No formal rehabilitation plan has been included for this specialist study.

Details pertaining to site rehabilitation will be included in the Rehabilitation

Plan for the mine.

Offset No formal offset strategy has been formulated for the project. It is

recommended that the impacts to the wetland areas be offset by managing

and enhancing the ecological state and services being offered by the

remaining wetland areas within the project area.

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8 Discussion

The Weltevreden study area is located within the quaternary catchment X11D; which is the

Komati River catchment. The major watercourse impacted upon is the Klein Komati River

and the quaternary catchment has been assigned a PES of C – moderately modified. Three

wetland units have been identified by NFEPA, namely the Weltevreden Pan and two isolated

seep; which have been allocated ranks 2, 2, and 6 respectively. Further to this, no necessary

or irreplaceable areas were identified, according to the Mpumalanga C-Plan, in order to meet

their objectives.

Wetlands on site make up a total area of 160.3 ha, which is largely attributable to extensive

hillslope seep area. HGM units on site were comprised of: valley bottom without a channel, a

single pan / depression and hillslope seeps (either linked to channels, pans or were

isolated).

Agricultural practices such as overgrazing and trampling, pasture conversions, damming and

crop planting in wet areas are largely responsible for the current impacts on the biodiversity

and water quality of the wetlands in the study area. While it is evident from the study that

these impacts have affected the ecological state of the wetlands, in addition to this, impacts

such as road and drainage channel construction and damming have seriously affected the

underlying hydrology (key driver) supporting the wetland areas. All of the wetlands within the

study area have been modified to some extent with 76.3% of the wetlands being moderately

modified (PES C) and 23.7% regarded as largely modified (PES D). The Weltevreden Pan

was allocated a PES of C (moderately modified).

The primary ecological service provided for by the wetland areas is the enhancement of

water quality. The specific services offered for each wetland unit according to Kotze et al.

(2007) are presented in Table 6-4.

The major impact anticipated from the proposed activity is direct loss of wetlands,

particularly hillslope seeps that lead to channels.

The cumulative impacts of the proposed development should be considered, owing to large-

scale mining development in the Mpumalanga Province. If valley bottom wetlands are

avoided, the cumulative impact is regarded as moderate. Further to this, the mitigation

hierarchy should be adhered to and efforts should be made to avoid and reduce impacts to

wetlands on site.

9 Recommendations

■ It is recommended that direct impacts to the wetland areas be restricted to the

opencast area. Additionally, the functioning of the wetland areas should be artificially

created so as to ensure the survival of the remaining wetland areas as well as their

ability to offer ecological services in the way of water quality enhancement continues.

Mitigation measures for the proposed mining activities are discussed below.

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■ DWAF has guidelines for drinking and live-stock watering water qualities as well for

aquatic ecosystems which should be incorporated into catchment management

strategies. It is recommended that water quality monitoring guidelines be included,

which will be water quality requirements to maintain sustainable ecological functioning

in the river/wetland. Surface water quality will become a greater issue because of the

proposed opencast mining. Issues such as storm water runoff carrying coal particles

into natural streams, dust from opencast mines settling in wetlands and rivers,

increased total dissolved solids, increased pH and increased electrical conductivity all

impact on wetland functioning by disturbing natural sediments in wetlands and directly

impacting and faunal and floral organisms critical to proper wetland functioning.

■ In order to minimize the impact of excessive sedimentation to the wetland areas it is

recommended that earth piles be vegetated and gabions used in areas of high runoff

potential to trap lose sediment. Additionally it is recommended to construct berms,

approximately 1.0m – 1.5m high for the length of area between the opencast

workings/soil stock piles and the wetland areas. The purpose of these berms would

be to intercept flows containing suspended soils and create a depositional

environment, inhibiting sediment introduction into the downslope wetland areas. It is

also recommended that current agricultural fields on the periphery of the opencast

area be rehabilitated to natural grasslands. This will minimise areas where lose

sediment is available a result of the agricultural practices and in addition create areas

which will contribute to erosion control and sediment trapping required for the mining

activities.

■ The coal should be stored and carefully managed to minimise dust emissions, water

can be sprayed onto them, so that wind doesn't blow particles of coal onto adjacent

systems and/or neighboring properties. An optional mitigation measures to prevent

the remote possibility of groundwater contamination is with the installation of an

impermeable liner under the stockpiles as a contingency against the possibility that

coal from untested portions of the mine could contaminate water to a greater degree

than the existing tests indicate. A detrimental effect of such a measure is the volume

of contaminated surface runoff collected by the drainage systems. The use of

impermeable liners is technically feasible but would represent substantial and

possibly, unnecessary expense. It is situated above an already disturbed area and

this disturbed area can be rehabilitated to minimize runoff from the stockpile into the

surrounding landscape. This can be achieved through vegetating the area and/or the

use of gabions as well as berms.

■ Formulate a wetland offset strategy for the wetland areas which will be mined. This

strategy could place emphasis on the management and enhancement of the

ecological services and overall state of the wetland areas within the project boundary

area,.

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10 Conclusions

It can be concluded that the findings from this wetland assessment show that no change in

wetland area, PES, EIS or ecological services has taken place since the initial surveys took

place for the report submitted in 2008 and that the former findings have been confirmed.

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CRONK J K, and SIOBHAN FENNESSY M, (2001). Wetland Plants: Biology and Ecology.

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Appendix A: CV’s of the Specialists

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Ms Crystal Rowe

Flora and Fauna Ecologist and Wetland Specialist

Biophysical Department

Digby Wells Environmental

EDUCATION

2011: BSc Honours (Botany) – Nelson Mandela Metropolitan University

2008-2001: Undergraduate BSc – Nelson Mandela Metropolitan University

EMPLOYMENT

June 2013 – Present: Digby Wells Environmental

December 2011 – June 2013: Natural Scientific Services CC

EXPERIENCE

June 2013 – Present: Digby Wells Environmental

Crystal was appointed by Digby Wells Environmental chiefly as a Flora and Fauna Ecologist

but also to assist in conducting wetland assessment studies. Crystal’s flora background aids

in her understanding on wetlands from a floral perspective. The wetland assessment studies

include in particular the delineation of wetland boundaries, classification of wetland units

according to the HGM Classification System, integrity description of the identified wetland

units, functional assessment of the identified wetland units and subsequent compilation of

management recommendations mitigation against the impacts. In addition, Crystal has also

completed a course in Tools for Wetland Assessments at Rhodes University (2011).

December 2011 – June 2013: Natural Scientific Services CC

Field work and report compilation for Biodiversity Baseline Assessments, Wetland

Assessments (WA) and Impact Assessments (IA).

PROJECT EXPERIENCE

Wetland Assessments

■ Wetland assessments throughout South Africa

■ Wetland studies in Northern Mozambique, and;

■ Wetland studies in Sierra Leone.

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Mr. Andrew Husted

Operations Manager

United Kingdom: Office Manager

Digby Wells Environmental

Education

2006 – 2007: BSc Masters in Aquatic Health – University of Johannesburg (UJ)

2005 – 2006: BSc Hons. Zoology – Aquatic Health – Rand Afrikaans University (RAU)

2005 – 2003: BSc Natural Science – Zoology & Botany (RAU)

Professional Registration

South African Council for Natural Scientific Professions (Membership No. 400213/11)

Accredited: South African Scoring System version 5 (SASS5)

Employment

August 2007 – Present: Digby Wells Environmental

January 2006 – June 2007: Econ@UJ, as an aquatic ecologist

Experience

Andrew is currently in the role of Operations Manager for the London office. This is a new

endeavour to establish and develop a sustainable office as the company’s global footprint

continues to grow. The primary responsibilities for the role include client liaison, project

management, staff management and office management.

He has been tasked with managing projects on local and international levels. This has

included the management of specialist studies which have either contributed to a larger

study or have been required for a strategic assessment. In addition to this, Andrew has

managed large scale mining projects on an international level.

His experience has included managing a multi-disciplinary department of scientists providing

specialist services in support of national and international requirements as well as best

practice guidelines, primarily focussing on the mining sector. In addition to managing the

department, Andrew was also expected to provide specialist technical input, most notably

focusing on water resource management. Information pertaining to the technical expertise of

Andrew include the following:

■ Aquatic ecological state assessments of rivers and dams;

■ Instream Flow Requirement or Ecological Water Requirement studies for river

systems;

■ Ecological wetland assessment studies, including the integrity (health) and functioning

of the wetland systems;

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■ Wetland offset strategy designs;

■ Wetland rehabilitation plans;

■ Monitoring plans for rivers and other wetland systems;

■ Toxicity and metal analysis of water, sediment and biota.

■ Fish telemetry assessment which included the translocation of fish as well as the

monitoring of fish in order to determine the suitability of the hosting system.

Training

■ Wetland and Riparian Delineation Course for Consultants (Certificate of Competence)

– DWAF 2008

■ The threats and impacts posed on wetlands by infrastructure and development:

Mitigation and rehabilitation thereof – Gauteng Wetland Forum 2010

■ Ecological State Assessment of Lentic Systems using Fish Population Dynamics –

University of Johannesburg/Rivers of Life 2010

■ Soil Classification and Wetland Delineation – Terra Soil Science 2010

■ Wetland Rehabilitation Methods and Techniques - Gauteng Wetland Forum 2011

■ Application of the Fish Response Assessment Index (FRAI) and Macroinvertebrate

Response Assessment Index (MIRAI) for the River Health Programme 2011

■ Tools for a Wetland Assessment (Certificate of Competence) – Rhodes University

2011

Publications

Tate, R.B. and Husted, A (2013 for review). Bioaccumulation of metals in Tilapia zillii

(Gervai, 1848) from an impoundment on the Badeni River, Cote D'Iviore. African Journal of

Aquatic Science.

O’Brien, G.C., Bulfin, J.B., Husted, A. and Smit, N.J. (2012). Comparative behavioural

assessment of an established and new Tigerfish (Hydrocynus vittatus) population in two

manmade lakes in the Limpopo catchment, Southern Africa. African Journal of Aquatic

Science.

Husted, A. (2009). Aspects of the biology of the Bushveld Smallscale Yellowfish

(Labeobarbus polylepis): Feeding biology and metal bioaccumulation in five populations. The

University of Johannesburg (Thesis).

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Appendix B: Wetland Delineation Methodology

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Wetland delineation

In accordance with the definition of a wetland in the National Water Act (NWA), vegetation is

the primary indicator of a wetland, which must be present under normal circumstances.

However, the soil wetness indicator tends to be the most important in practices. The

remaining three indicators are then used in a confirmatory role. The reason for this is that the

response of vegetation to changes in the soil moisture regime or management are relatively

quick and may be transformed, whereas the morphological indicators in the soil are

significantly more permanent and will hold the indications of frequent and prolonged

saturation long after a wetland has been drained (perhaps several centuries) (DWAF, 2005).

In accordance with DWAF guidelines (2005) the wetland delineation procedure considers

four attributes to determine the limitations of the wetland. The four attributes are:

Terrain Unit Indicator

Terrain Unit Indicator (TUI) areas include depressions and channels where water would be

most likely to accumulate. These areas are determined with the aid of topographical maps,

aerial photographs and engineering and town planning diagrams (these are most often used

as they offer the highest degree of detail needed to accurately delineate the various zones of

the wetland) (DWAF, 2005).

Soil Form Indicator

Hydomorphic soils are taken into account for the Soil Form Indicator (SFI) which will display

unique characteristics resulting from prolonged and repeated water saturation (DWAF,

2005). The continued saturation of the soils results in the soils becoming anaerobic and thus

resulting in a change of the chemical characteristics of the soil. Iron and manganese are two

soil components which are insoluble under aerobic conditions and become soluble when the

soil becomes anaerobic and thus begin to leach out into the soil profile. Iron is one of the

most abundant elements in soils and is responsible for the red and brown colours of many

soils. Resulting from the prolonged anaerobic conditions, iron is dissolved out of the soil, and

the soil matrix is left a greying, greenish or bluish colour, and is said to be “gleyed”. Common

in wetlands which are seasonally or temporarily saturated is a fluctuating water table, these

results in alternation between aerobic and anaerobic conditions in the soil (DWAF, 2005).

Iron will return to an insoluble state in aerobic conditions which will result in deposits in the

form of patches or mottles within the soil. Recurrence of this cycle of wetting and drying

over many decades concentrates these insoluble iron compounds. Thus, soil that is gleyed

and has many mottles may be interpreted as indicating a zone that is seasonally of

temporarily saturated (DWAF, 2005).

Soil Wetness Indicator

In practice, the Soil Wetness Indictor (SWI) is used as the primary indicator (DWAF, 2005).

Hydromorphic soils are often identified by the colours of various soil components. The

frequency and duration of the soil saturation periods strongly influences the colours of these

components. Grey colours become more prominent in the soil matrix the higher the duration

and frequency of saturation in a soil profile (DWAF, 2005). A feature of hydromorphic soils

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are coloured mottles which are usually absent in permanently saturated soils and are most

prominent in seasonally saturated soils, and are less abundant in temporarily saturated soils

(DWAF, 2005). In order for a soil horizon to qualify as having signs of wetness in the

temporary, seasonal or permanent zones, a grey soil matrix and/or mottles must be present.

Vegetation Indicator

If vegetation was to be used as a primary indicator, undisturbed conditions and expert

knowledge are required (DWAF, 2005). Due to this uncertainty, greater emphasis is often

placed on the SWI to delineated wetland areas. In this assessment the SWI has been relied

upon to delineated wetland areas in addition, the identification of indicator vegetation

species and the use of plant community structures has been used to validate these

boundaries. As one moves along the wetness gradient from the centre of the wetland to the

edge, and into adjacent terrestrial areas plant communities undergo distinct changes in

species composition. Valuable information for determining the wetland boundary and

wetness zone is derived from the change in species composition. When using vegetation

indicators for delineation, emphasis is placed on the group of species that dominate the plant

community, rather than on individual indicator species (DWAF, 2005).

The health of wetlands

Table B-11-1: Health categories used by WET-Health for describing the integrity of wetlands

i) Description ii) Score iii) Category

iv) Unmodified, natural v) 0 – 1 vi) A

vii) Largely natural with few modifications. A

slight change in ecosystem processes is

discernable and a small loss of natural habitats

and biota may have taken place.

viii) 1.1 –

2 ix) B

x) Moderately modified. A moderate

change in ecosystem processes and loss of

natural habitats has taken place but the natural

habitat remains predominantly intact

xi) 2.1 –

4 xii) C

xiii) Largely modified. A large change in

ecosystem processes and loss of natural habitat

and biota and has occurred.

xiv) 4.1 -

6 xv) D

xvi) The change in ecosystem processes

and loss of natural habitat and biota is great but

some remaining natural habitat features are still

recognizable.

xvii) 6.1 –

8 xviii) E

xix) Modifications have reached a critical

level and the ecosystem processes have been

modified completely with an almost complete loss

of natural habitat and biota.

xx) 8.1 –

10 xxi) F

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